Proteorhodopsins act as light-driven outward proton pumps mainly at neutral and alkaline pH, however, mirror proteorhodopsins are known to operate only at acidic pH. Here, the authors report the detailed structural and functional characterization of pH mirror proteorhodopsin SpaR as well as its diverse biological roles.
- Ivan S. Okhrimenko
- Kirill Kovalev
- Valentin I. Gordeliy